Carn Dearg sits to the south of Loch Ossian and is only really accessed by the train from Corrour Halt on the West Highland Line. Carn Dearg is normally climbed in conjunction with Sgor Gaibhre. The two hills lie deep in the heart of Rannoch Moor. Carn Dearg is the intersection of 3 ridges. The SW is a long ridge of roughly 4km that drops down slowly to the floor of Rannoch Mor east of the Blackwater Reservoir. The NW ridge drops down over easy slopes to the southern shores of Loch Ossian and Corrour station this is the normal route of accent. Finally the NE ridge leads over a low col to connecting Munro Sgor Gaibhre.
Carn Dearg is not the most well known peak in the area and there are no aspects to the hill that makes it a particularly technically difficult climb. You do however get a great feeling of solitude from the hill as the only real way of climbing is by taking the train in.